Objectives: a) To participate in the cooperative studies of the various therapeutic regimens in acute leukemia, chronic leukemia, multiple myeloma, lymphoma and solid tumors to be studied by the Acute Leukemia Cooperative Group B. The toxicity and therapeutic range of new agents will be determined by Phase I studies; the frequency, extent and duration of remission with new agents will be evaluated in Phase II studies; and the relative efficacy of various therapeutic regimens at different stages of the diseases will be determined by Phase III studies. b) To continue serologic screening of multiple myeloma patients. The qualitative and quantitative changes in protein production will also be determined in lymphoma patients as indicated. c) To utilize the case material for the cooperative chemotherapy studies for ancillatory investigations of some of the biological, biochemical and immunological aspects of the hematologic malignancies under study, such as: (1) Effect of treatment of myeloma patients on synthesis of normal immunoglobulins, (2) Immunological profile of patients with leukemia and myeloma, (3) Immunological responses of leukemic patients to leukemic cell antigens.